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Ars reviews GarageBand for iPad: a killer app for budding songwriters

Apple has moved GarageBand from the desktop to the iPad, re-imagining it as an …

All the keyboard instruments are laid out in the same general way. A row of virtual keys line the bottom of the screen. A narrow strip of controls is directly above the keys, and a larger upper portion with instrument-specific controls is at the top.

(The very top edge of the screen always shows the main "control bar," with controls for accessing the 8-track mixer, picking a project, setting the overall tempo and key, and more. We'll discuss these controls in detail a little later when we get into recording.)

GarageBand offers a number of ways to adjust the virtual keys to suit your playing style or the song at hand. The size of the virtual keys can be adjusted to show one, two, or three octaves. There's also a setting to show two rows of keys at the same time, making it possible to use one hand to play bass notes while another plays melody. Note that showing a second row of keys hides the extra instrument adjustments, though—something to keep in mind before recording a two-handed passage. The keys themselves are velocity sensitive, thanks to the iPad's built-in accelerometer, so tapping harder on the keys will produce louder sounds (and in some cases, a modified timber or attack). In our experiments, there appear to be three discernible velocity levels.

The Keyboard offers a number of ways to configure its virtual keys.

Using two rows of keys could be useful for playing bass and melody parts at the same time.

The control strip above the virtual keyboard gives the player ways to control, from left to right: octaves, sustain, the effect of swiping along the keyboard while playing, a scale control, arpeggiator, and the aforementioned keyboard adjustment control.

The octave control has left, middle, and right buttons. The left and right button have arrows to suggest that tapping them moves the displayed octaves up or down. To give you an idea how the control works, suppose I have the keyboard set to display two octaves, and my key is set to C; by default I should see C3 and C4. Tapping the right arrow gives me access to C4 and C5. Depending on the instrument, you can move up or down four octaves, from C-2 up to C8. The middle button will display the offset from the default, such as "-2" or "+1." Tapping the middle button will bring the keyboard back to the default octave.

The sustain control is a simple switch. In the left position, you can press and hold a key to sustain a note. In the right position, tapping a key will automatically sustain the note. The effect of the sustain depends significantly on the instrument. It works much like the sustain pedal on the piano, for instance, with the sound slowly decaying over time. On some synths, however, the note will continue to play indefinitely. On other synths, it didn't seem like the sustain control did anything at all.

The "key control," as Apple calls it, lets you change what happens when you swipe along the keyboard. Glissando does what you would typically expect—swiping left or right moves up or down a note. Tapping this control switches it to "scroll" mode, so hitting a key and swiping left or right will shift the displayed range of octaves on the keyboard. If the piece you are trying to play involves moving up and down the keyboard, this mode could prove easier to use while playing than tapping left or right on the octave control. Synths also offer a third "pitch" mode. Tapping a key and swiping will shift the pitch of the current note up or down, letting you "bend" notes up or down as much as you like, or play a whole melody while swiping left and right.

Setting a scale mode makes sure you only play the "right-sounding" notes.

The scale control allows you to constrain the keyboard to a particular scale mode, including major, minor, major and minor pentatonic, major and minor blues, and a few other less common (at least in Western pop music) modes such as Dorian, Mixolydian, Japanese, Klezmer, and Southeast Asian. Setting the scale this way is particularly useful for figuring out melodic lines or improvising a solo. The keyboard will only display "keys" for the notes in the scale, so you don't have to remember (or even know) which sharps or flats belong in the particular scale. You can effectively play these notes with reckless abandon, and they will always sound more or less "right." Choosing a scale mode is particularly easy on those will little or no knowledge of music theory, since GarageBand will adjust the list of possible modes in the order of ones that sound best depending on the overall key set for the current song.

The arpeggiator control will likely be the most fun for the average user, particularly when paired with synthesizer sounds. Arpeggiated chords are chords that have each note played in a sequence instead of all at once. The effect is probably most commonly heard in classical piano and rock guitar, though if you're a fan of dance music, you'll recognize arpeggiated chords right away. Sequencers and synths often have an arpeggiator which will automatically play notes in a sequence when the user holds down the keys for the notes in a chord.

The arpeggiator can generate automatic note sequences—commonly used in dance music—based on the notes of the keys that are held down. Note order, rate, and octave range all effect the generated pattern.

GarageBand's arpeggiator lets you choose the note order, note rate, and octave range to change how the arpeggiated chords are generated. You can choose up, down, up and down, random, or "as played" for the note order. For the note rate, you can choose between 1/4 and 1/32 notes, dotted 1/4 and 1/32 notes, or 1/4 and 1/16 triplets. And you can choose between one and four octaves for the chord range. The default is 1/16 notes in two octaves ordered as played, which sounds quite good in a wide range of music, but it's easy—and fun!—to experiment with difference combinations of settings to find one that suits your song best.

Finally, the keyboard settings button lets you change your keyboard configuration as mentioned earlier, choosing between one, two, and three octaves shown on one or two rows of keys. Here you can turn on or off the velocity control, which lets you adjust how the virtual keyboard reacts to different hard or soft presses. You can set how wide the range of velocity must be to change the sound, as well as how hard or soft it has to be. I found the default range to require a fairly hard tap to really hit the top end of the velocity map, and it felt uncomfortable to play this way, so I adjusted the control downward slightly. You can also turn off the key control button, presumably to avoid hitting it while in the middle of playing or recording.